scholarly journals Modeling the Depletion and Recovery of the Outer Radiation Belt During a Geomagnetic Storm: Combined MHD and Test Particle Simulations

2018 ◽  
Vol 123 (7) ◽  
pp. 5590-5609 ◽  
Author(s):  
Kareem A. Sorathia ◽  
Aleksandr Y. Ukhorskiy ◽  
Viacheslav G. Merkin ◽  
Joseph F. Fennell ◽  
Seth G. Claudepierre
Keyword(s):  
Geomagnetic Storm ◽  
Test Particle ◽  
Radiation Belt ◽  
Outer Radiation Belt ◽  
Particle Simulations

PROBLEMS OF THE OUTER RADIATION BELT FORMATION AND TOPOLOGICAL FEATURES OF HIGH LATITUDE MAGNETOSPHERE

2021 ◽  
Vol 44 ◽  
pp. 7-11
Author(s):  
Elena Antonova ◽  
Keyword(s):  
Geomagnetic Storm ◽  
High Latitude ◽  
Radiation Belt ◽  
Ring Current ◽  
Outer Part ◽  
Auroral Oval ◽  
Plasma Pressure ◽  
Relativistic Electrons ◽  
Outer Radiation Belt ◽  
Topological Features

We analyzed the problems of formation of the outer radiation belt (ORB) taking into consideration the latest changes in our understanding of the high-latitude magnetospheric topology. This includes strong evidence that the auroral oval maps to the outer part of the ring current, meanwhile the ORB polar boundary maps inside the auroral oval. Our analysis also includes the variation of the plasma pressure distribution and the time of the acceleration of relativistic electrons during geomagnetic storm. It is shown that the maximum of ORB is formed after the geomagnetic storm in the region of plasma pressure maximum. The position of this maximum agrees with the prediction of the ORB formation theory based on the analysis of ring current development during storm. We emphasize the role of adiabatic processes in the ORB dynamics and the importance of the substorm injections during storm recovery phase for the formation of enhanced fluxes of ORB electrons after the storm.

scholarly journals The cusp: a window for particle exchange between the radiation belt and the solar wind

2006 ◽  
Vol 24 (11) ◽  
pp. 3131-3137 ◽  
Author(s):  
X.-Z. Zhou ◽  
T. A. Fritz ◽  
Q.-G. Zong ◽  
Z. Y. Pu ◽  
Y.-Q. Hao ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Open Field ◽  
Test Particle ◽  
Radiation Belt ◽  
Magnetospheric Convection ◽  
Cusp Region ◽  
Particle Simulations ◽  
Particle Exchange ◽  
Field Lines

Abstract. The study focuses on a single particle dynamics in the cusp region. The topology of the cusp region in terms of magnetic field iso-B contours has been studied using the Tsyganenko 96 model (T96) as an example, to show the importance of an off-equatorial minimum on particle trapping. We carry out test particle simulations to demonstrate the bounce and drift motion. The "cusp trapping limit" concept is introduced to reflect the particle motion in the high latitude magnetospheric region. The spatial distribution of the "cusp trapping limit" shows that only those particles with near 90° pitch-angles can be trapped and drift around the cusp. Those with smaller pitch angles may be partly trapped in the iso-B contours, however, they will eventually escape along one of the magnetic field lines. There exist both open field lines and closed ones within the same drift orbit, indicating two possible destinations of these particles: those particles being lost along open field lines will be connected to the surface of the magnetopause and the solar wind, while those along closed ones will enter the equatorial radiation belt. Thus, it is believed that the cusp region can provide a window for particle exchange between these two regions. Some of the factors, such as dipole tilt angle, magnetospheric convection, IMF and the Birkeland current system, may influence the cusp's trapping capability and therefore affect the particle exchanging mechanism. Their roles are examined by both the analysis of cusp magnetic topology and test particle simulations.

Corotating drift resonant electrons in Saturn's radiation belt: theory and observational evidence

2020 ◽  
Author(s):  
Yixin Hao ◽  
Yixin Sun ◽  
Elias Roussos ◽  
Ying Liu ◽  
Chongjing Yuan ◽  
...  
Keyword(s):  
Electric Field ◽  
Test Particle ◽  
Equatorial Plane ◽  
Radiation Belt ◽  
Observational Evidence ◽  
Diagnostic Feature ◽  
Electron Radiation ◽  
Radial Transport ◽  
Resonant Energy ◽  
Particle Simulations

<p>Corotating drift resonant (CDR) electrons, of which the gradient and curvature drift could cancel the corotation around the Saturn, could get efficiently radial transported when exposed to the Saturnian global convective electric field. Such fast radial transport could lead to significant adiabatic acceleration and therefore supply for the electron radiation belt population. In this work, the nonlinear trapping nature of the corotating drift resonance is investigated. Electrons trapped inside the resonant island preform a banana-like orbit in the equatorial plane. We present an estimation of the trapping limit in L shell and energy for the resonant electrons with varying first adiabatic invariant, which could be directly compared to CASSINI observations. The estimation of the trapping period also indicates that trapped electrons takes times of more hours to close their orbit than the traveling electrons. The evolution in energy spectrogram driven by Saturn's convection and corotation has also been predicted by our test particle simulations. We suggest  that the bifurcation of the 'zebra stripes' near the corotation drift resonant energy could be a diagnostic feature of the nonlinear CDR. Observations from MIMI/LEMMS with similar zebra stripes and the bifurcation have been found as predicted, proving that the electrons in Saturn's radiation belt are being transported radially by the convection and that corotating drift resonant could be a significant candidate for the plenishing of the Saturn's electron radiation belt.   </p>

scholarly journals Global MHD test particle simulations of >10 MeV radiation belt electrons during storm sudden commencement

2007 ◽  
Vol 112 (A9) ◽  
pp. n/a-n/a ◽  
Author(s):  
B. T. Kress ◽  
M. K. Hudson ◽  
M. D. Looper ◽  
J. Albert ◽  
J. G. Lyon ◽  
...  
Keyword(s):  
Test Particle ◽  
Radiation Belt ◽  
Sudden Commencement ◽  
Storm Sudden Commencement ◽  
Particle Simulations ◽  
Radiation Belt Electrons
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